Patent Literature 1: JP 2011-004048 A
There is known a network of Ethernet (registered trademark), which connects Ethernet switches serving as relaying apparatuses in a loop circuit in order to enhance backup redundancy of the communication path. Each Ethernet switch has several ports, which include particular ports that are connected in the loop circuit. In a subject Ethernet switch, a broadcast frame is transmitted from a first particular port, and the transmitted broadcast frame then returns to a second particular port of the subject Ethernet switch itself. The broadcast frame having returned is transferred so as to be again transmitted from the first port of the subject Ethernet switch. Such transfer is repeated infinitely, causing the broadcast frame to continue to circle or go round forever within the network. Such phenomenon which causes broadcast frames to continue to circle or go round is called a broadcast storm.
Techniques solving broadcast storms include STP (Spanning Tree Protocol) and RSTP (Rapid Spanning Tree Protocol) (refer to Patent Literature 1).